Love the ZEPHYRS. They are very nice, and IMHO they knit very similar to the Harmony.
I have 3 pairs of the tips only. Very nice. And very affordable. A great interchangeable investment for newbie knitters, too.
Hate Denise. It's that doggone cable mostly. It's a poor investment IMO. I know many knitters love 'em...but I'm not one of 'em. They were my first investment into interchangeables. That was in pre-Knitpicks-Options days.
The Boye Needlemaster interchangeable system was available before Denise...but they were way more money. I eventually purchased a set of them, too...for $40 at a Joann's sale. I've used them from time-to-time...but the cables are kinky.